This application claims the benefit of Korean Application No. 2001-7339, filed Feb. 14, 2001, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a display apparatus, and more particularly, to an illumination system for a display apparatus for use by an individual, such as a Head Mount Display apparatus (HMD).
2. Description of the Related Art
Generally, an HMD is mounted on a face or a head of a user in the form of eyeglasses or a helmet, for allowing the user to obtain image information. The HMD apparatus is a type of image displaying apparatus for individual use, which is usually used in Virtual Reality systems, flight simulators, etc. FIG. 1 illustrates a conventional head mount display apparatus 100, in which light is emitted from a light source 11, and an optical path thereof is altered by a series of optical units 12 and 13. Accordingly, the light is condensed on an image generator 14 such as a liquid crystal display (LCD) or the like, generating an image which is magnified and projected on eyes 10 of an observer through a projected lens 15.
The optical unit 12 diffuse-reflects the light emitted from the light source 11, and alters the optical path thereof. The optical unit 12 can be a prism, a diffuse reflectance plate, or the like. The optical unit 13 reflects the light, which is diffuse-reflected by the optical unit 12 to a different optical path. By reflecting the light, the optical unit 13 condenses the light on the image generator 14. optical unit 13 can be a polarization filter such as a polarizing beam splitter (PBS), or the like.
According to the conventional HMD apparatus 100, since the prism or the diffuse reflectance plate that comprises the optical unit 12 has a planar light reflecting surface, marginal rays (a) and (b) of the light, which are spaced relatively far away from a main optical axis (c), are usually lost, and the optic efficiency is deteriorated.
Accordingly, it is an object of the present invention to overcome the above-mentioned problems of the related art, and accordingly, it is an object of the present invention to provide an illumination system for a display apparatus, and more particularly, to provide an effective illumination system for a display apparatus for individual use, capable of reducing electric power consumption and lengthening a life span thereof through an improved light utilization efficiency.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
The above object is achieved with an illumination system for a display apparatus according to the present invention, including a light source; an image generator generating an image by using a light emitted from the light source; and an optical condenser having a light reflective surface condensing the light emitted from the light source on the image generator by diffuse-reflecting the light. The light reflective surface of the optical condenser has a predetermined degree of curvature. According to the present invention, the optical condenser includes a reflecting mirror or a prism having a light reflective surface curved by a predetermined degree of curvature, diffuse-reflecting the light emitted from the light source and condensing the light on the image generator.